Generally, a motor brake device is installed on a motor for decelerating, stopping or accurately positioning the motor. The conventional motor brake device comprises a brake lining, a rotor hub, a fixing plate, an armature plate and an armature base. The armature plate is located near the armature base. The brake lining is arranged between the fixing plate and the armature plate. The rotor hub is disposed within a corresponding slot of a brake friction plate. Moreover, the rotor hub matches the shaft of the motor. Consequently, the rotations of the rotor hub and the brake friction plate may be driven by the motor.
When the motor is normally operated and an electric current flows through the motor brake device, the armature plate is magnetically attracted by the armature base, so that the armature plate is moved away from the brake lining. At the same time, the rotations of the rotor hub and the brake friction plate are driven by the shaft of the motor. On the other hand, when the electric current is interrupted, the armature plate is no longer magnetically attracted by the armature base. Consequently, the compressed springs within the armature base are restored to their original positions, and the armature plate is moved toward the brake lining. Under this circumstance, the brake lining is in contact with the armature plate and the fixing plate. In response to the friction force between the brake lining and the armature plate, the braking efficacy of the motor is achieved.
Although the conventional motor brake device is able to achieve the function of decelerating or stopping the motor, there are still some drawbacks. For example, if there is a large production tolerance between the rotor hub and the brake friction plate of the motor brake device or if there is a seam between the rotor hub and the brake friction plate after a long use time, the operation of the motor brake device may generate vibration and noise or result in radial deflection between the rotor hub and the brake friction plate. Under this circumstance, the transmission precision of the motor brake device is impaired, and the performance of the motor brake device is adversely affected.
Therefore, there is a need of providing an improved motor brake device so as to overcome the above drawbacks.